Functional traits, drought performance, and the distribution of tree species in tropical forests of Ghana

Tropical forests occur along a rainfall gradient where annual amount, the length and intensity of dry season vary and water availability shapes therefore strongly the distribution of tree species. Annual rainfall in West Africa has declined at a rate of 4% per decade, and climate change models predict a further reduction in rainfall and an increase in frequency and intensity of drought. This will have large consequences for the diversity, composition and distribution of tropical tree species. Understanding the factors that shape tree species distribution will help to understand current forest functioning and to predict the potential impact of climate change on forests. In this thesis, I used a combination of forest inventory data, greenhouse and field experiments to determine the responses of 10-23 species to drought and shade, and analyse the underlying mechanisms. I addressed 4 questions: (1) What is the relative importance of rainfall and temperature on tree species distribution? (2) How do tree species acclimatise to drought and shade in terms of their physiology, morphology, growth and survival? (3) What morphological and physiological traits determine species drought performance and distribution? (4) How do seedling survival, growth and physiology vary between dry and wet forests, and does drought tolerance and growth determine species distribution along the rainfall gradient? Forest inventory data showed that the distribution of 95% of 20 species was significantly associated with annual rainfall, 60% with rainfall seasonality, 45% with isothermality and 40% with temperature seasonality. Thus, a reduction in annual rainfall, and an increase in frequency and intensity of drought as predicted by climate change models may affect the distribution of many tree species. A greenhouse experiment indicated that shade facilitated the survival of seedlings subjected to drought, rather than reducing it. This contrasts with the trade-off hypothesis that suggests a stronger impact of drought in shade conditions. Across 23 species, I found a trade-off between drought avoidance (by a deciduous leaf habit during drought) and physiological drought tolerance (by having tough and persistent tissues that allow plants to function during drought) strategies. These strategies were closely associated with species’ shade tolerance and growth rates. A suite of functional traits predicted drought survival and tree species position on the rainfall gradient. Across species, drought survival was enhanced by having less biomass allocation to transpiring leaves, a low leaf area per unit plant mass, and by dense and tough leaf and wood tissues that allow plants to function during drought. The field experiment showed that drought survival (and growth) in the dry forest relative to the wet forest correlated negatively with species position on the rainfall gradient. Hence, species that survive and grow relatively well in dry forests are found at the drier end of the rainfall gradient. This suggests that species sensitivity to low water availability determines the distribution of tree species. The predicted increase in drought frequency and intensity may, therefore, cause a shift in the distribution of tree species in tropical forests.</p

The effects of drought and shade on the performance, morphology and physiology of Ghanaian tree species

In tropical forests light and water availability are the most important factors for seedling growth and survival but an increasing frequency of drought may affect tree regeneration. One central question is whether drought and shade have interactive effects on seedling growth and survival. Here, we present results of a greenhouse experiment, in which seedlings of 10 Ghanaian tree species were exposed to combinations of strong seasonal drought (continuous watering versus withholding water for nine weeks) and shade (5% irradiance versus 20% irradiance). We evaluated the effects of drought and shade on seedling survival and growth and plasticity of 11 underlying traits related to biomass allocation, morphology and physiology. Seedling survival under dry conditions was higher in shade than in high light, thus providing support for the “facilitation hypothesis” that shade enhances plant performance through improved microclimatic conditions, and rejecting the trade-off hypothesis that drought should have stronger impact in shade because of reduced root investment. Shaded plants had low biomass fraction in roots, in line with the trade-off hypothesis, but they compensated for this with a higher specific root length (i.e., root length per unit root mass), resulting in a similar root length per plant mass and, hence, similar water uptake capacity as high-light plants. The majority (60%) of traits studied responded independently to drought and shade, indicating that within species shade- and drought tolerances are not in trade-off, but largely uncoupled. When individual species responses were analysed, then for most of the traits only one to three species showed significant interactive effects between drought and shade. The uncoupled response of most species to drought and shade should provide ample opportunity for niche differentiation and species coexistence under a range of water and light conditions. Overall our greenhouse results suggest that, in the absence of root competition shaded tropical forest tree seedlings may be able to survive prolonged drought

Exploring the linkages between project managers’ mindset behaviour and project leadership style in the Ghanaian construction industry

Purpose: Leadership encapsulates a process of influencing others to understand what needs to be done and how it can be done. The related area of mindset behaviour which moderates leadership styles adopted in various industries has hitherto received scant academic attention in a construction context. This paper thus explores the linkages between project manager’s mindset behaviour and project leadership style in the construction industry. Design/Methodology/Approach: Literature reviewed provides the basis for a questionnaire data collection instrument developed to gather primary data from construction professionals in the Ghanaian Construction Industry (GCI). A quantitative research strategy is then adopted using the Relative Importance Index (RII) to determine the level of significance of the leadership and mindset archetypes. A Pearson’s correlation test was run to ascertain whether the mindset behaviour of project managers has a significant impact upon the type of leadership style. Findings: The study’s results indicate that democratic, transformational and situational leadership styles were prevalent leadership styles in the GCI. The analysis also revealed that project managers favoured the ‘growth mindset’ and that furthermore, this style had a moderate positive relationship with democratic and transformational leadership styles. Conversely, a fixed mindset had a low positive relationship with autocratic and situational leadership styles but a low negative relationship with transformational leadership style. Practical and theoretical implications: This research provides sufficient data for project managers to identify the type of mindset to nurture (the growth mindset is recommended) and the effective leadership style to be employed. This study engenders wider discussion on mindset behaviour and project leadership style in developing countries. Moreover, the findings present policy makers and practitioners with the leadership styles to promote and develop (democratic, transformational and situational) and mindset behaviour (growth mindset) to ensure project success in Ghana and other developing countries. Originality/value: This research represents the first comprehensive study appraising the linkages between project manager’s mindset behaviour and project leadership style in the construction industry. Empirical data presented bridges the identified knowledge gap that exists on the lack of theoretical understanding of the influence that project managers’ mindset has on leadership styles in the GCI

The effect of milk type and fortification on the growth of low-birthweight infants: An umbrella review of systematic reviews and meta-analyses

Approximately 15% of infants worldwide are born with low birthweight (<2500 g). These children are at risk for growth failure. The aim of this umbrella review is to assess the relationship between infant milk type, fortification and growth in low-birthweight infants, with particular focus on low- and lower middle–income countries. We conducted a systematic review in PubMed, CINAHL, Embase and Web of Science comparing infant milk options and growth, grading the strength of evidence based on standard umbrella review criteria. Twenty-six systematic reviews qualified for inclusion. They predominantly focused on infants with very low birthweight (<1500 g) in high-income countries. We found the strongest evidence for (1) the addition of energy and protein fortification to human milk (donor or mother's milk) leading to increased weight gain (mean difference [MD] 1.81 g/kg/day; 95% confidence interval [CI] 1.23, 2.40), linear growth (MD 0.18 cm/week; 95% CI 0.10, 0.26) and head growth (MD 0.08 cm/week; 95% CI 0.04, 0.12) and (2) formula compared with donor human milk leading to increased weight gain (MD 2.51 g/kg/day; 95% CI 1.93, 3.08), linear growth (MD 1.21 mm/week; 95% CI 0.77, 1.65) and head growth (MD 0.85 mm/week; 95% CI 0.47, 1.23). We also found evidence of improved growth when protein is added to both human milk and formula. Fat supplementation did not seem to affect growth. More research is needed for infants with birthweight 1500–2500 g in low- and lower middle–income countries

Attitudes towards persons with mental health conditions and psychosocial disabilities as rights holders in Ghana: a World Health Organization study

Background: There are currently major efforts underway in Ghana to address stigma and discrimination, and promote the human rights of those with mental health conditions, within mental health services and the community, working with the World Health Organization’s QualityRights initiative. The present study aims to investigate attitudes towards people with lived experience of mental health conditions and psychosocial disabilities as rights holders. Methods: Stakeholders within the Ghanaian mental health system and community, including health professionals, policy makers, and persons with lived experience, completed the QualityRights pre-training questionnaire. The items examined attitudes towards coercion, legal capacity, service environment, and community inclusion. Additional analyses explored how far participant factors may link to attitudes. Results: Overall, attitudes towards the rights of persons with lived experience were not well aligned with a human rights approach to mental health. Most people supported the use of coercive practices and often thought that health practitioners and family members were in the best position to make treatment decisions. Health/mental health professionals were less likely to endorse coercive measures compared to other groups. Conclusion: This was the first in-depth study assessing attitudes towards persons with lived experience as rights holders in Ghana, and frequently attitudes did not comply with human rights standards, demonstrating a need for training initiatives to combat stigma and discrimination and promote human rights

Methicillin Resistant Staphylococcus aureus Transmission in a Ghanaian Burn Unit:The Importance of Active Surveillance in Resource-Limited Settings

Objectives:Staphylococcus aureus infections in burn patients can lead to serious complications and death. The frequency of S. aureus infection is high in low- and middle-income countries presumably due to limited resources, misuse of antibiotics and poor infection control. The objective of the present study was to apply population genomics to precisely define, for the first time, the transmission of antibiotic resistant S. aureus in a resource-limited setting in sub-Saharan Africa.Methods:Staphylococcus aureus surveillance was performed amongst burn patients and healthcare workers during a 7-months survey within the burn unit of the Korle Bu Teaching Hospital in Ghana.Results: Sixty-six S. aureus isolates (59 colonizing and 7 clinical) were obtained from 31 patients and 10 healthcare workers. Twenty-one of these isolates were ST250-IV methicillin-resistant S. aureus (MRSA). Notably, 25 (81%) of the 31 patients carried or were infected with S. aureus within 24 h of admission. Genome comparisons revealed six distinct S. aureus clones circulating in the burn unit, and demonstrated multiple transmission events between patients and healthcare workers. Further, the collected S. aureus isolates exhibited a wide range of genotypic resistances to antibiotics, including trimethoprim (21%), aminoglycosides (33%), oxacillin (33%), chloramphenicol (50%), tetracycline (59%) and fluoroquinolones (100%).Conclusion: Population genomics uncovered multiple transmission events of S. aureus, especially MRSA, within the investigated burn unit. Our findings highlight lapses in infection control and prevention, and underscore the great importance of active surveillance to protect burn victims against multi-drug resistant pathogens in resource-limited settings

Police views of suicidal persons and the law criminalizing attempted suicide in Ghana: A qualitative study with policy implications

The penal code of Ghana condemns suicide attempt. The present study sought to explore the views of the police on persons who attempt suicide and the law criminalizing the act. Qualitative in-depth interviews were used to explore the views of 18 officers of the Ghana Police Service. Data were analyzed using thematic analysis technique. Findings showed that the police officers profiled suicide attempters as needy, enigmatic, ignorant, and blameworthy. Majority (n = 14) of them disagreed with the law and suggested a repeal, whereas only four of them agreed with the law. Regardless of their positions on criminalization, they showed an inclination to help, rather than arrest, when confronted with such persons in line of their duty. Educating the police on suicidal behavior may help to deepen their understanding and help improve the way they handle suicidal persons. This may also strengthen police suicide prevention gatekeeping obligations

Detection of Mycobacterium ulcerans by the Loop Mediated Isothermal Amplification Method

In order to develop a simple and rapid test that can be used to diagnose Buruli ulcer under field conditions, we modified the conventional LAMP assay by using a disposable pocket warmer as a heating device for generating a constant temperature for the test reaction and employed the use of crude sample preparations consisting of boiled and unboiled extracts of the clinical specimen instead of using purified DNA as the diagnostic specimen. Thirty clinical specimens from suspected Buruli ulcer patients were investigated by the modified LAMP (or pocket warmer LAMP) and the conventional LAMP, as well as IS2404 PCR, a reference method for the detection of Mycobacterium ulcerans. There was no significant difference in the detection rate (63–70%) in all of the methods when purified samples were used for the tests. On the other hand the use of crude specimen preparation resulted in a drop in detection rate (30–40%). This study demonstrates that the LAMP test can be used for rapid detection of M. ulcerans when purified DNA preparations are used. With further improvements in the sample reaction, as well as in specimen purification, the pocket warmer LAMP may provide a simple and rapid diagnostic test for Buruli ulcer

Hypoxia-Induced Down-Regulation of Neprilysin by Histone Modification in Mouse Primary Cortical and Hippocampal Neurons

Amyloid β-peptide (Aβ) accumulation leads to neurodegeneration and Alzheimer's disease (AD). Aβ metabolism is a dynamic process in the Aβ production and clearance that requires neprilysin (NEP) and other enzymes to degrade Aβ. It has been reported that NEP expression is significantly decreased in the brain of AD patients. Previously we have documented hypoxia is a risk factor for Aβ generation in vivo and in vitro through increasing Aβ generation by altering β-cleavage and γ-cleavage of APP and down-regulating NEP, and causing tau hyperphosphorylation. Here, we investigated the molecular mechanisms of hypoxia-induced down-regulation of NEP. We found a significant decrease in NEP expression at the mRNA and protein levels after hypoxic treatment in mouse primary cortical and hippocampal neurons. Chromatin immunoprecipitation (ChIP) assays and relative quantitative PCR (q-PCR) revealed an increase of histone H3-lysine9 demethylation (H3K9me2) and a decrease of H3 acetylation (H3-Ace) in the NEP promoter regions following hypoxia. In addition, we found that hypoxia caused up-regulation of histone methyl transferase (HMT) G9a and histone deacetylases (HDACs) HDAC-1. Decreased expression of NEP during hypoxia can be prevented by application with the epigenetic regulators 5-Aza-2′-deoxycytidine (5-Aza), HDACs inhibitor sodium valproate (VA), and siRNA-mediated knockdown of G9a or HDAC1. DNA methylation PCR data do not support that hypoxia affects the methylation of NEP promoters. This study suggests that hypoxia may down-regulate NEP by increasing H3K9me2 and decreasing H3-Ace modulation